Individuals and businesses increasingly utilize UAVs to perform a variety of flight missions or tasks. Indeed, because of the reduced cost of UAVs relative to chartering manned aerial vehicles, businesses and individuals can engage in a variety of flight activities that were traditionally cost-prohibitive. For example, it is becoming increasingly common to utilize UAVs to perform flight missions for capturing digital aerial images of a site in construction, land management, mining, or other applications.
In particular, some conventional flight systems utilize UAVs to generate three-dimensional models of a site. For example, some conventional digital image systems capture a plurality of digital aerial images of a site with a plurality of survey ground control points and then generate a three-dimensional model utilizing the digital aerial images and the known location of the survey ground control points. In particular, such conventional systems utilize survey ground control points to precisely georeference the three-dimensional model.
Although such conventional flight systems allow users to utilize a UAV to generate three-dimensional models of a site, they also have a number of problems. For example, it is often time-consuming and expensive to place and/or identify known survey ground control points in relation to a site. Indeed, in implementations that repeatedly perform flight missions over a particular site, the amount of time and effort required to repeatedly place, measure, and maintain survey ground control points can significantly increase the cost of utilizing a UAV to capture digital aerial images and generate a three-dimensional model. Furthermore, placing, measuring, and maintaining survey ground control points introduces a significant risk of human error.
Rather than using ground control points, some conventional flight systems utilize GPS technology to identify the location of a UAV in taking digital aerial images. For example, some conventional flight systems analyze code embedded in a signal transmitted from a satellite to a UAV to determine the distance between the UAV and the satellite. Utilizing this approach, conventional flight systems can identify the position of the UAV (or approximate position of the camera affixed to the UAV), and then utilize the position of the UAV in combination with a digital aerial image to generate a three-dimensional model.
Although these conventional GPS flight systems can identify a location of a UAV, they also have their own problems. For example, conventional GPS flight systems are not very precise, and are only able to determine the location of a UAV (or camera) within a range of decimeters. This inaccuracy in the location of a UAV (or camera) directly translates into inaccuracies in any resulting three-dimensional model. Moreover, inaccuracies in the location of the UAV can increase the amount of computational resources required to generate an accurate three-dimensional model from a plurality of digital aerial images.
Accordingly, a number of problems and disadvantages exist with conventional systems for utilizing a UAV to capture digital aerial images and accurately generate three-dimensional models (e.g., by identifying accurate camera positioning data).